Do I need a permit and Title 24 to replace my furnace or AC with a heat pump?

Yes, in most cases. Replacing heating or cooling equipment is an alteration under California's Energy Code, and the California Energy Commission's 2025 compliance manual says the certificate of compliance must be submitted with the building permit application and registered with an ECC provider when field verification is required. A heat pump change-out usually requires both.

What the Energy Code requires on a change-out

• Duct sealing and testing. Replacing an air handler, installing or replacing an outdoor unit, replacing a packaged system, or replacing a coil triggers duct sealing verified by an ECC rater (the program formerly called HERS). The target is 10 percent total leakage or 7 percent to outside; if neither can be met, all accessible leaks must be sealed and verified by visual inspection and a smoke test.
• Exceptions. Ducts already sealed, tested and certified by an ECC rater, duct systems with less than 40 feet of duct, and ducts containing asbestos.
• Garages. When altered ducts or equipment are in a garage, the target is 6 percent leakage, or sealing verified by visual inspection and smoke test.
• Refrigerant charge. When a refrigerant-containing component of a heat pump is installed or replaced, refrigerant charge must be field verified in all climate zones, along with minimum airflow.
• Thermostat. A digital setback thermostat is required when a refrigerant-containing component is added or replaced.
• Heating fuel. A replacement heating system may not use electric resistance as the primary heat source, with limited exceptions. The manual's examples point to a heat pump or a gas system as the prescriptive options.

When the whole system is new

If the air handler, all heating and cooling equipment and the entire duct system are new, the manual treats it as an entirely new system. That brings in load calculations, duct insulation and fan efficacy requirements, a 5 percent duct leakage target, and attic insulation and air sealing requirements when the air handler and ducts sit in a vented attic.

What your city may ask for

Menlo Park's submittal list for heat pump replacements is a typical example: a permit application, the signed Title 24 form CF1R-ALT-02-E, product specifications, and a lot plan showing equipment location and distance to property lines, plus the panel location and the circuit amperage. Menlo Park also has a local amendment requiring a heat pump instead of a new air conditioning condenser when one is replaced. Other cities have their own reach codes.

Don't forget electrical capacity

Menlo Park notes that a heat pump needs more electrical power than a gas furnace. Check whether your panel and service can carry the new load before you choose equipment.

What this means for your MEP plans

A simple like-for-like change-out may need only forms and a site plan, while a new duct system or a panel change benefits from mechanical and electrical sheets. MEP Plans USA prepares residential mechanical and electrical plans and Title 24 reports. See heat pump considerations, field verification testing and Title 24 reports. Requirements vary by city, so confirm with your building department.

Sources: energy.ca.gov, energy.ca.gov, menlopark.gov, energy.ca.gov.